The Kapteyn Package is a collection of Python modules and applications developed by the computer group of the Kapteyn Astronomical Institute, University of Groningen, The Netherlands. The purpose of the package is to provide tools for the development of astronomical applications with Python.

CFITSIO is a library of C and Fortran subroutines for reading and writing data files in FITS (Flexible Image Transport System) data format. CFITSIO provides simple high-level routines for reading and writing FITS files that insulate the programmer from the internal complexities of the FITS format. CFITSIO also provides many advanced features for manipulating and filtering the information in FITS files.

article on space.com

This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero) vacuum energy.

astLib is a set of Python modules that provides some tools for research astronomers. It can be used for astronomical plots, some statistics, common calculations, coordinate conversions, and manipulating FITS images with World Coordinate System (WCS) information through PyWCSTools - a simple wrapping of WCSTools by Doug Mink. PyWCSTools is distributed (and developed) as part of astLib.

SM is a plotting programme written by Robert Lupton (

APLpy (the Astronomical Plotting Library in Python) is a Python module aimed at producing publication-quality plots of astronomical imaging data in FITS format. The module uses Matplotlib, a powerful and interactive plotting package. It is capable of creating output files in several graphical formats, including EPS, PDF, PS, PNG, and SVG.

Welcome to my Galaxy Luminosity Function Engine. You can use the form below to create your own B-band luminosity function (LF) of a volume-limited galaxy population. The assumption is that the shapes of the type-specific LF of ellipticals (E), lenticulars (S0), spirals (Sp), dwarf irregulars (dIrr), and dwarf ellipticals (dE) are invariant of the environment and thus the observed variation of the overall LFs from galaxy clusters to the field has its origin in the different type mixtures (known as the morphology-density relation).